mirror of https://github.com/acidanthera/audk.git
76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
/** @file
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AMD Sev Dxe driver. This driver is dispatched early in DXE, due to being list
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in APRIORI. It clears C-bit from MMIO and NonExistent Memory space when SEV is
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enabled.
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Copyright (c) 2017, AMD Inc. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD
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License which accompanies this distribution. The full text of the license may
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be found at http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <PiDxe.h>
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/MemoryAllocationLib.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include <Library/DxeServicesTableLib.h>
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#include <Library/MemEncryptSevLib.h>
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EFI_STATUS
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EFIAPI
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AmdSevDxeEntryPoint (
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IN EFI_HANDLE ImageHandle,
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IN EFI_SYSTEM_TABLE *SystemTable
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)
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{
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EFI_STATUS Status;
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EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;
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UINTN NumEntries;
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UINTN Index;
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//
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// Do nothing when SEV is not enabled
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//
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if (!MemEncryptSevIsEnabled ()) {
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return EFI_UNSUPPORTED;
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}
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//
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// Iterate through the GCD map and clear the C-bit from MMIO and NonExistent
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// memory space. The NonExistent memory space will be used for mapping the MMIO
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// space added later (eg PciRootBridge). By clearing both known MMIO and
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// NonExistent memory space can gurantee that current and furture MMIO adds
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// will have C-bit cleared.
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//
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Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);
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if (!EFI_ERROR (Status)) {
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for (Index = 0; Index < NumEntries; Index++) {
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CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;
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Desc = &AllDescMap[Index];
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if (Desc->GcdMemoryType == EfiGcdMemoryTypeMemoryMappedIo ||
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Desc->GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
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Status = MemEncryptSevClearPageEncMask (0,
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Desc->BaseAddress,
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EFI_SIZE_TO_PAGES(Desc->Length),
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FALSE);
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ASSERT_EFI_ERROR (Status);
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}
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}
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FreePool (AllDescMap);
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}
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return EFI_SUCCESS;
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}
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